ifdef Q_?S_* cleanup

- clear up some Q_OS_LINUX vs. Q_OS_UNIX
- clear up Q_WS_* vs. Q_OS_* (relatively theoretical exercise)
- use proper #if-#else cascades instead of free-standing #ifs

src/shared/proparser/profileevaluator.cpp

@@ -48,7 +48,7 @@
 #ifdef Q_OS_UNIX
 #include <unistd.h>
 #include <sys/utsname.h>
-#elif defined(Q_OS_WIN32)
+#else
 #include <Windows.h>
 #endif
 #include <stdio.h>